Process for measuring insulation resistance in inverters with multi-point topology and inverters with multi-point topology

摘要

To measure insulation resistance in an inverter (1), which has a DC link (2) and a bridge circuit (4) connected to the DC link (2) for driving an AC current via a bridge center (5), the bridge center (5) is connected to a grounding point ( 21) and the bridge center (5) connected to the earthing point (21) is connected in succession to two voltage-different points of the unearthed DC voltage intermediate circuit (2) by means of the bridge circuit (4). A current flowing from the two voltage-different points to the grounding point (21) is measured. The two voltage-different points of the ungrounded DC voltage intermediate circuit (2) are selected from a group of points which, in addition to the two end points of the ungrounded DC voltage intermediate circuit (2), comprise at least one intermediate voltage point (11) of the DC voltage intermediate circuit (2) such that those between the two voltage different Points and earth (15) applied electrical voltages do not exceed a predetermined voltage limit.